Using silicone o-rings in dual action irrigation pump

ABSTRACT

A disposable dual-action reciprocating pump part includes a piston and a cylinder, and multiple silicone O-rings. The piston is configured to move bi-directionally inside the cylinder. The multiple silicone O-rings are configured to seal the piston against the cylinder.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 35 U.S.C. § 120 of U.S. patentapplication Ser. No. 16/585,264, filed Sep. 27, 2019, which claims thebenefit of U.S. Provisional Patent Application 62/786,406, filed Dec.29, 2018, U.S. Provisional Patent Application 62/786,402, filed Dec. 29,2018, U.S. Provisional Patent Application 62/786,404, filed Dec. 29,2018, and U.S. Provisional Patent Application 62/786,407, filed Dec. 29,2018. The entire contents of these applications are incorporated hereinin their entirety.

FIELD OF THE INVENTION

The present invention relates generally to medical pumps, andparticularly to single-use medical pumps.

BACKGROUND OF THE INVENTION

Various designs for medical pumps that may be one-time used wereproposed in the patent literature. For example, U.S. Patent ApplicationPublication 2008/0195058 describes apparatus and methods for engaging apumping cartridge with a pump drive. In certain embodiments, thecartridge, comprising a cylinder and a movable piston assembly, isinitially assembled or subsequently positioned so that the distancebetween the attachment point on the piston assembly for coupling to adrive assembly, and a reference point on the cylinder, is greater thanthe maximal distance that will be encountered during normal oscillationof the piston during use. The cartridge, in certain embodiments may bepressed into a drive assembly having means for immobilizing thecartridge and means for coupling the piston assembly to the driveshaft.In certain embodiments, when the cartridge is fully inserted into thedrive assembly, the piston is pressed into the cylinder sufficiently toestablish a selected distance so that the piston shaft is in the properposition to engage with a coupling mechanism carried on the driveshaft.

As another example, U.S. Patent Application Publication 2015/0327875describes a system for aspirating thrombus that includes a catheterhaving an aspiration lumen configured to couple to a vacuum source. Thesystem further has a disposable tubing set having a first conduitconfigured to couple the supply lumen of the aspiration catheter to afluid source, and a pump component associated with the first conduit andconfigured to detachably couple to a drive unit.

Various designs for controlling an output flow of a medical pump areknown in the art. For example, U.S. Patent Application Publication2013/0123689 describes a breast pump apparatus comprising a vacuum pumpand a variable-volume buffer volume coupled together in fluidcommunication. The apparatus also includes a breast-receiving portioncoupled to the vacuum pump and the buffer volume such that the vacuumpump is operable to generate negative pressure at the breast-receivingportion to stimulate milk expression, and the negative pressuregenerated at the breast-receiving portion can be controlled bycontrolling the buffer volume.

As another example, U.S. Patent Application Publication 2003/0220608describes a method, system and apparatus for performing peritonealdialysis. To this end, in part, a method of controlling pressure in amedical fluid pump is provided. The method includes the steps ofcontrolling a pump member acceleration during a first portion of a pumpstroke and adaptively changing the pump member velocity during a secondportion of the pump stroke.

U.S. Patent Application Publication 2017/0326282 describes hemodialysisand similar dialysis systems. According to one aspect, a blood pump ofthe system is configured to pump blood to a dialyzer of a hemodialysisapparatus, wherein the blood pump comprising a pneumatically actuated orcontrolled reciprocating diaphragm pump. In an embodiment, the diaphragmof the pump comprises a flexible membrane formed or molded to generallyconform to a curved inner wall of a pumping chamber or control chamberof the pump, wherein the diaphragm is pre-formed or molded to have acontrol side taking a convex shape, so that any elastic tension on thediaphragm is minimized when fully extended into a control chamber of thepump.

U.S. Pat. No. 5,921,951 describes an apparatus for pumping fluid at asteady rate. A first drive chamber having a movable outer surface, and asecond drive chamber having a movable outer surface are provided. Theapparatus further includes a block having a plurality of internalpassages including a first passage for receiving the fluid into theblock and a second passage for discharging the fluid from the block atthe steady rate. The block has first and second internal chambers whichare in fluid connection with the first and second passages. The firstinternal chamber has a first flexible surface for mating with themovable outer surface of the first drive chamber, and the secondinternal chamber has a second flexible surface for mating with themovable outer surface of the second drive chamber. At least one actuatoris provided for applying positive pressure to the first flexible surfacewhile simultaneously applying negative pressure to the second flexiblesurface and for applying negative pressure to the first flexible surfacewhile simultaneously applying positive pressure to the second flexiblesurface. The actuator is respectively coupled to the first and secondflexible surfaces by the first and second drive chambers.

U.S. Pat. No. 3,771,918 describes a multiple stage, linear,reciprocating, balanced-unopposed compressor that is driven by an analogof a turnbuckle with the drive having first and second pairs ofassociated recirculating ball bearing nuts and screws. The ball bearingnuts are constrained against axial displacement and are driven by asource of rotary power. The pairs of recirculating ball bearing nuts andscrews are oppositely threaded and the screws are coupled together forreciprocation together. The screws are successively braked to producereciprocation. The screw under power compresses gas in a plurality ofstages in an isomer by driving a plurality of pistons. When the powerstroke of a screw is completed, its brake is released and the otherscrew braked to compress gas in a second isomer identical with thefirst. The stroke of the compressor is variable for warmup purposes.

Various types of sealing elements for use in a medical pump wereproposed in the patent literature. For example, U.S. Patent ApplicationPublication 2014/0224829 describes a fluid pump device that is operableby a drive and actuating system. The fluid pump device includes a pumpmanifold, a plurality of pump cylinders, a plunger reciprocally operablein each of the pump cylinders, and at least one inlet selector valve.The inlet selector valve may be located laterally outboard of the pumpcylinders and extend generally parallel to the pump cylinders. In anembodiment, O-ring seals may be made of any type of suitable elastomericmaterial including polyurethane, silicone or EPDM rubbers, depending,for example, whether the sealed parts are static or are moving one withrespect to the other.

As another example, U.S. Patent Application Publication 2011/0144586describes portable infusion devices, systems, and methods of using thesame for dispensing materials. In some cases, the devices, systems andmethods may be used for infusing a material such as medicament, e.g.,insulin, into a body in need thereof. In some instances, the seals usedmay be made from materials such as butyl, silicone, polyurethanes or thelike having a shore hardness of about 70 A.

U.S. Patent Application Publication 2011/0106003 describes a peritonealdialysis system that includes a disposable cassette having an interfacethat includes at least one pump aperture. An at least one piston headmoveable out of and retractable into the at least one pump aperture tomove a corresponding pumping portion of a flexible sheet of thedisposable cassette, the piston head moving within a vacuum chamber, thevacuum chamber enabling a vacuum to be pulled around the piston head tothe flexible sheet of the disposable cassette. In an embodiment, a shaftseal, which can be of any known type, hereafter referred to as anO-ring, is also placed within a housing between a shaft opening and thepiston to maintain the vacuum within the chamber.

SUMMARY OF THE INVENTION

An embodiment of the present invention provides a pump device includinga rotary motor, a compartment for insertion of a disposable pump part,and one or more pulsation-reduction elements. The disposable pump partincludes an input port, an output port, and a dual-action reciprocatingassembly. The input port is configured for intaking fluid. The outputport is configured for outputting the fluid. The dual-actionreciprocating assembly is configured for pumping the fluid. The assemblyincludes a single piston and a rod configured to be coupled to therotary motor, so as to drive the piston. The one or morepulsation-reduction elements are configured to reduce a pulsation in theoutputted fluid, caused by the single-piston dual-action reciprocatingassembly.

In some embodiments, the one or more pulsation-reduction elements areconfigured to reduce variations in motion speed of the single piston.

In some embodiments, the one or more pulsation-reduction elementsinclude a balloon damper which is fitted in the output port of the pumppart.

In an embodiment, the one or more pulsation-reduction elements include amechanical smoothing mechanism including a guide channel (e.g., a slit)and a bar that are configured to couple a shaft of the rotary motor tothe rod. The bar is coupled to the shaft to move rotationally in theguide channel, and a profile of the guide channel is configured tospeed-up and a slow-down a reciprocating motion of the rod by rotationalmotion the of the bar.

In another embodiment, the one or more pulsation-reduction elementsinclude a processor that is configured to vary a rotation speed of therotary motor.

There is additionally provided, in accordance with an embodiment of thepresent invention, a disposable pump part for inserting into acompartment of a pump device, the disposable pump part including aninput port, an output port, and a single-piston dual-actionreciprocating assembly. The input port is configured for intaking fluid.The output port is configured for outputting the fluid. The dual-actionreciprocating assembly is configured for pumping the fluid. The assemblyincludes a single piston, non-return valves, a rod, and a mechanicalpulsation-reduction element. The non-return valves are configured toopen and close interchangeably in response to the pumping by the singlepiston, so as to provide dual-action reciprocating pumping. The rod isconfigured to be coupled to a rotary motor of the pump device, so as todrive the single piston. The mechanical pulsation-reduction element isconfigured to reduce a pulsation in the outputted fluid, caused by thesingle-piston.

In some embodiments, the input port, the output port and the assemblyare configured to be fitted in the pump device, and subsequently removedfrom the pump device at the end of use.

There is further provided, in accordance with an embodiment of thepresent invention, a manufacturing method, including assembling asingle-use pump part including (a) an input port for intaking fluid, (b)an output port for outputting the fluid, and (c) a single-pistondual-action reciprocating assembly for pumping the fluid. The assemblyincludes (i) non-return valves, configured to open and closeinterchangeably in response to the pumping to provide dual-actionreciprocating pumping, (ii) a rod configured to be coupled to a rotarymotor, so as to drive the dual-action reciprocating assembly, and (iii)one or more pulsation-reduction elements that are configured to reduce apulsation in the outputted fluid, caused by the single-pistondual-action reciprocating assembly. The assembled pump part is packagedin a sterile package.

There is furthermore provided, in accordance with an embodiment of thepresent invention, a manufacturing method, including inserting adisposable single-piston dual-action reciprocating pump part into acompartment of a pump device. The pump part includes one or morepulsation-reduction elements that are configured to reduce a pulsationin fluid outputted from the pump part, caused by the single-pistondual-action reciprocating assembly. An input port of the pump part isconnected to a fluid supply. An output port is connected to a fluidsupply line of a medical device. The pump device is operated from acontrol panel of the pump device.

Another embodiment of the present invention provides a disposablesingle-piston dual-action reciprocating pump part that includes a singlepiston, an output port, and a balloon damper. The output port isconfigured for outputting fluid pumped by the single piston. The balloondamper is fitted in the output port, and the balloon damper isconfigured to suppress a pulsation in a flow rate of the outputtedfluid.

In some embodiments, the balloon damper is configured to accept a shapeof a chamber into which the balloon is fitted.

In some embodiments, the balloon damper is configured to suppress thepulsation in the flow rate of the outputted fluid by the balloon damperreturning, when the output flow rate is reduced, to an uncompressedvolume and pushing extra fluid through the output port.

There is additionally provided, in accordance with an embodiment of thepresent invention, a manufacturing method including partially assemblinga disposable dual-action reciprocating pump part having an output portfor outputting fluid. A balloon damper is fitted in the output port, andthe balloon damper is configured to suppress a pulsation in a flow rateof the outputted fluid. the pump part assembly is then completed.

In some embodiments, the manufacturing method further includes packagingthe assembled pump part in a sterile package.

Another embodiment of the present invention provides a disposabledual-action reciprocating pump part that includes an input port, anoutput port, a single-piston dual-action reciprocating assembly forpumping the fluid, and a mechanical smoothing mechanism. The input portis configured for intaking fluid. The output port is configured foroutputting fluid pumped by the single piston. The single-pistondual-action reciprocating assembly for pumping the fluid includes asingle piston, and a rod configured to be coupled to a shaft of a rotarymotor. The mechanical smoothing mechanism includes a guide channel and abar, which couples the shaft of the rotary motor to the rod such that aprofile of the guide channel, in which the bar moves rotationally, isconfigured to speed-up and slow-down a reciprocating motion of the rodby rotational motion the of the bar.

In some embodiments, the pump part further includes non-return valves,configured to open and close interchangeably in response to pumping bythe single piston, so as to provide dual-action reciprocating pumping.

In some embodiments, the pump part further includes a balloon damper,which is fitted in the output port, and the balloon damper is configuredto suppress a pulsation in a flow rate at of the outputted fluid.

In some embodiments, the pump part further includes multiple siliconeO-rings, which are configured to seal the piston against a cylinder ofthe pump part.

Another embodiment of the present invention provides a disposabledual-action reciprocating pump part that includes a piston and acylinder, and multiple silicone O-rings. The piston is configured tomove bi-directionally inside the cylinder. The multiple silicone O-ringsare configured to seal the piston against the cylinder.

In some embodiments, at least one of the silicone-made O-rings is fixedrelative to the piston and is configured to slide against the cylinder.

There is further provided, in accordance with an embodiment of thepresent invention, a manufacturing method, including partiallyassembling a disposable dual-action reciprocating pump part having apiston and a cylinder, and the piston is configured to movebi-directionally inside the cylinder. Multiple silicone made are fitted,which are configured to seal the piston against the cylinder. Theassembly of the pump part in then completed.

In some embodiments, fitting multiple silicone made includes fitting atleast one silicone made O-ring over the piston.

The present invention will be more fully understood from the followingdetailed description of the embodiments thereof, taken together with thedrawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic volume rendering of a medical pump devicecomprising a disposable single-piston dual-action pump part, inaccordance with an embodiment of the present invention;

FIG. 2 is a cross-sectional view of the disposable single-pistondual-action pump part of FIG. 1 , in accordance with an embodiment ofthe present invention;

FIG. 3 is a cross-sectional view of a disposable single-pistondual-action pump part including a balloon damper, in accordance with anembodiment of the present invention;

FIG. 4 is a graph describing motion of the piston of the disposabledual-action pump of FIG. 1 as a function of an angle of the rotary motorof the pumping system, in accordance with an embodiment of the presentinvention;

FIG. 5 is a schematic volume rendering of a mechanical smoothingmechanism, in accordance with an embodiment of the present invention;

FIG. 6 is a flow chart describing a design method of portion of themechanical smoothing mechanism of FIG. 5 , in accordance with anembodiment of the present invention.

FIG. 7 is a cross-sectional view of the disposable single-pistondual-action pump part of FIG. 1 including silicone O-rings, inaccordance with an embodiment of the present invention; and

FIG. 8 is a flow chart describing a manufacturing method of thedisposable single-piston dual-action pump part of FIG. 1 , in accordancewith an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS Overview

In some medical applications, a disposable medical pump is required toprovide an output flow at a constant flow rate. At the same time, suchmedical pump has to be a low-cost product. While some types of low-costpumps, such as certain peristaltic pumps, may produce a steady flow,peristaltic pumps typically contain plastic components that areconstantly flexed during pumping. The constant flexing of plastic partsgenerates electrical noise which may be picked up by some medicaldevices used in a medical procedure and degrade their performance.

Embodiments of the present invention that are described hereinafterprovide a disposable single-piston dual-action reciprocating pump part,free of flexing, which includes and/or is coupled to one or morepulsation-reduction elements that are configured to reduce pulsation inthe output flow, caused by the reciprocating motion of the single pistonof the pump part.

In the context of the disclosed embodiments, pulsation is defined as aperiodically recurring alternate increase and decrease of the outputflow of the disclosed pump part, which is correlated with thereciprocating motion of the piston. A steady flow of fluid can thus beviewed as a complete lack of pulsation.

The disclosed disposable pump part is configured to be easily fitted(i.e., inserted) in a compartment of a medical pump device (pump devicealso named hereinafter “pumping system”). The pump part is configuredfor a “one-off” single use, and is subsequently readily removed from thepump device, e.g., at the end of use. The disposable pump part separatesthe part of the pump that is in contact with fluid from the pump driver.The entire disposable pump part does not require sterilization beforeuse, and is mostly made of plastics.

In some embodiments, a pump device is provided, which comprise (a) arotary motor, (b) a compartment for insertion of a disposable pump part,and (c) one or more pulsation-reduction elements included in the pumpdevice. The disposable pump part comprises (i) an input port forintaking fluid, and an output port for outputting the fluid, (ii) adual-action reciprocating assembly for pumping the fluid, wherein theassembly comprises a single piston and a rod configured to be coupled tothe rotary motor, so as to drive the piston.

Examples of pulsation-reduction elements include a damping balloon, aprocessor, a guide channel of a mechanical smoothing mechanism, theguide channel having a non-linear profile, which are all describedbelow. In general, the disclosed techniques are applicable to any otherpulsation-reduction element that operates in conjunction with a singlepiston pump.

The balloon damper, which is fluid-coupled to the fluid flowing throughthe output port of the pump part, acts as a smoothing “capacitor” forthe output flow. The disclosed balloon damper is fitted into a chamberinside the pump part. When the output flow is reduced the balloonreturns to its original uncompressed volume and pushes extra fluidthrough the output port, thereby reducing the pulsation output to aminimum.

Therefore, the balloon regulates the output flow rate that is modulatedby the piston motion by: (i) the balloon being compressed during theconstant speed travel section of the piston, and (ii) at the end-pointsof piston travel, when output pressure falls, the balloon expands,increasing the flow rate from the lower value caused by the pistonchanging direction. In this solution, the balloon damper is part of anoutput port of the pump part, all of which are disposable.

The processor element controls the pump motor rotation speed, so thatexcept for the end-points of its travel, the piston travels at aconstant speed. At the piston travel end points, the processor variesthe rotation speed of the motor to reduce the pulsation.

Alternatively or additionally, the speeding up and slowing down of thepiston (i.e., of the rod) is achieved in some embodiments mechanically,utilizing a mechanical smoothing mechanism that the pump device (i.e.,pumping system) may comprise. The disclosed mechanical smoothingmechanism couples a rod that is part of the single-use pump part to ashaft of a rotary motor of the pumping device, to convert the rotationof the motor shaft into a periodic variable speed motion of the rod.

To convert motion, the mechanical smoothing mechanism comprises a barthat is coupled to the shaft and is free to move in a guide channelhaving a non-linear profile. That way, the disclosed smoothing mechanismcauses the piston of the pump part, which is fitted on the rod, toaccelerate just before reaching travel end-points at which the pistonhalts. The disclosed piston motion act to compensate for the diminishingflow rate at the piston turning points. In an embodiment, the design ofthe disclosed mechanical smoothing mechanism further takes into accountattenuation of the flow rate along the output path, to provide variablespeed piston motion that induces a uniform flow.

Some embodiments of the present invention provide a disposablesingle-piston dual action reciprocating pump part comprising siliconemade O-rings. The silicone made O-rings seal the piston against acylinder, so as to enable pumping fluid as the piston movesbi-directionally inside the cylinder. In some embodiments, at least oneof the silicone-made O-rings is fixed relative to the piston and isconfigured to slide against the cylinder

Silicone made O-rings typically exhibit poor tear resistance, abrasionand tensile strength. The poor abrasion resistance of a silicone madeO-ring means that such O-ring is generally considered unsuitable for useas a seal with moving parts. In some embodiments of the presentinvention, however, since the part is intended for “one-off” single use,the silicone made O-ring is also single-use and therefore the abovedrawbacks do not come into play. Moreover, the velocity of the piston iskept low enough to ensure the silicone O-ring fulfills its task reliablyin a “one-off” single use.

Using low cost O-ring in a pump part intended for “one-off” single usemay lower the cost of such pump part, and by so increase the adoption ofdisposable pumps in medical applications such as intravenous infusion ofmedications.

The disclosed low-cost disposable single-piston dual-action pump withthe disclosed techniques for the suppression of output flow pulsation,may be used in medical procedures in which, for example, using adisposable peristaltic pump may introduce electrical disturbances. Forexample, the disclosed single-use pump part can be used with anirrigated a radiofrequency cardiac ablation catheter, without addingelectrical noises to low-amplitude electrophysiological signals sensedby other devices. The disclosed low-cost pump part may thereforeincrease the adoption of disposable pumps in medical procedures.

System Description

FIG. 1 is a schematic volume rendering of a medical pump device 100comprising a disposable single-piston dual-action pump part 10, inaccordance with an embodiment of the present invention. The entire pumppart (part 10) is configured to be easily fitted in device 100 for asingle use and readily removed from device 100 at the end of use.

Device 100 further comprises a rotary pump motor 30, which is connectedto the pump via a connection mechanism (not marked in the figure) thatconverts the rotary action of the pump motor into a reciprocating motionof dual-action pump part 10.

Dual-action pump part 10 has a fluid input port 14, to which a fluidsupply is connected, and a fluid output port 16, which can be connected,for example, to a fluid supply line of a medical device, such as anirrigation port of a radiofrequency ablation catheter. Device 100 is astand-alone device operated and monitored from a control panel 50.

Inset 25 shows pump part 10 that is a single part configured to befitted into device 100. The only interfaces of the part are the fluidinput port 14, fluid output port 16, and a moving rod 12 which iscoupled to move a piston inside pump part 10 to provide the pumpingaction.

The example illustration shown in FIG. 1 is chosen purely for the sakeof conceptual clarity. Only elements relevant to the invention aredescribed, whereas many other parts included in device 100 are omittedfor simplicity. For example, the disclosed single-use pump part 10 isconnected to rotary pump motor 30 via a connecting rod and a screwmechanism. The screw mechanism converts the rotary action of the pumpmotor into a reciprocating motion of the connecting rod.

The example illustration shown in inset 25 is chosen purely for the sakeof conceptual clarity. In alternative embodiments, the industrial designof pump part 10 may be different, so as to fit other designs of medicalpump device 100.

Disposable Dual Action Reciprocating Pump Assembly

FIG. 2 is a schematic, pictorial illustration of the disposablesingle-piston dual-action pump part 10 of FIG. 1 , in accordance with anembodiment of the present invention. As seen, pumping part 10 is aone-part element that is configured to be fitted into device 100, withthe only interfaces of the part being the fluid input port 14, fluidoutput port 16, and a moving rod 12 which is coupled to move a pistoninside pump part 10 to provide the pumping action, as described below.

As seen, rod 12 drives a piston 18 inside a cylinder in a dual directionpumping action. Four non-return valves 22 open and close interchangeably(in pairs) to provide dual-action pumping. The reciprocating motion ofpiston 18, being usable at both opposing directions, causes fluid to bepumped from input port 14 into output port 16 in a largely continuousflow.

Moreover, by using such a dual-stroke configuration, pump part 10 iscapable of pumping fluid largely continuously in a wide range of flowrates, from several ml/min to several tens of ml/min, and in a wideoutput pressure range, from sub PSI to several tens of PSI.

Pump part 10 is mostly made of low-cost plastics parts, such asnon-return valves 22, that allow the one-use model of the disclosed pumpdevice.

The example illustration shown in FIG. 2 is chosen purely for the sakeof conceptual clarity. In alternative embodiments, the industrial designof pump part 10 may be different, so as to fit other designs of device100. Only elements relevant to the invention are described, whereas manyother components included in pump part 10, such as O-rings, are notdescribed for simplicity.

Using Balloon as Damper for Port of a Pump

FIG. 3 is a cross-sectional view of a disposable single-pistondual-action pump part 11 including a balloon damper 40, in accordancewith an embodiment of the present invention. As seen, balloon 40 isfitted inside pump part 11 at the exit port of part 11. Pump part 11functions as described for part 10 in FIG. 2 , with the only changebetween parts 10 and 11 being smoothing the output flow profile of part10 using balloon damper 40.

To establish a low and slowly varying flow rate of pump part 11, balloon40 is configured to be compressed by surrounding fluid during theconstant speed travel section of piston 18. At the piston end points,when fluid pressure drops, the balloon expands, increasing the flow ratefrom the lower value caused by the piston changing direction. Inset 45shows a graph that demonstrates the more uniform flowrate 55 when usingballoon 40, as compared with a flowrate 53 profile demonstrated withoutusing balloon 40. As seen by the shaded area, towards end points −X₀ and+X₀, the output flow of the pump drops substantially unless balloondumper 40 is used.

In some embodiment, balloon 40 has a special half-crescent cylindricalshape, which best fit an available space inside part 11, so as tomaximize the volume of the balloon and by so to maximize the dampingeffect of balloon over pulsations in the output flow.

The example illustration shown in FIG. 3 is chosen purely for the sakeof conceptual clarity. The shape of balloon 40 and the shape, location,and number of channels 44 may vary.

Reducing Pulsation in Dual-Action Reciprocating Pump

FIG. 4 is a graph describing motion of the piston of the disposabledual-action pump of FIG. 1 as a function of an angle of the rotary motorof the pumping system, in accordance with an embodiment of the presentinvention.

The disclosed graphs 52 and 55, are derived by a designer from arequirement for an outflow, seen as graph being be as uniform aspossible.

Periodic graph 52 shows piston position as a function of shaft angle ofthe rotary driving motor. As seen, near turning points of piston travel(i.e., about rotary angles 0, π, 2π . . . ), the piston position, X,depends non-linearly on the shaft angle. An underlying cause of thevariable speed motion of the piston is seen in graph 55, in which thepiston speed V_(X) is increased just before and after piston speeddecelerates as piston instantaneously halts at a cylinder turning end.

As noted above, a processor inside system 100 may instruct the system tovary the output flow rate, for example, by a combination of speeding upand slowing down the rotation of the motor, so as to reduce a pulsation.

FIG. 5 is a schematic volume rendering of mechanical smoothing mechanism40, in accordance with an embodiment of the present invention. In someembodiments, mechanical smoothing mechanism 40 is used for achieving adesired profile of the output flow of part 10, such as profile 60.

As seen, rod 12 is coupled to a guide hub 47 having a guide channel 48.A cylinder head 42 of mechanism 40 is coupled to a rotary shaft 41 ofthe driving motor (not seen). Guide hub 47 is coupled to head 42 by abar 46 that is screwed into head 42 so that bar 46 rotates with rotaryshaft 41. Because of guide channel 48, guide hub 47 is not rotationallycoupled to rod 12, rather element 47 moves back and forth in a variablespeed motion induced by bar 46 pushing and pulling element 47 (and withit rod 12 and hence piston 18) as bar 46 moves rotationally along guidechannel 48, forcing guide hub 47 to translate rod 12 along its axis inaccordance with the path defined by guide channel 48.

Guide channel 48 profile is designed to convert the rotation of shaft 41into the variable speed profile 55 V(X) of rod 12, seen in inset 45, asa function of the piston travel between turning ends −X₀ and +X₀ of thecylinder inside pump part 10.

The example illustration shown in FIG. 5 is chosen purely for the sakeof conceptual clarity. Only elements of mechanical smoothing mechanism40 relevant to the invention are described, whereas many other partsthat mechanical smoothing mechanism 40 may include, such as screws, areomitted for simplicity.

FIG. 6 is a flow chart describing a design method of the mechanicalsmoothing mechanism 40 of FIG. 5 , in accordance with an embodiment ofthe present invention. The process begins with defining a required,constant as possible, output flow profile of pump part 10, at an outputflow requirement step 70. Next, based on required profile of output flowprovided at step 70, a designer calculates piston velocity profile 55,at a piston velocity calculation step 72. Using the velocity profile,the designer calculates a profile of guide channel (e.g., slit) 48 ofmechanical smoothing mechanism 40 that will produce the required therequired output flow profile of pump part at a mechanical guide channelprofile calculation step 74. Finally, the designer saves the design ofmechanical smoothing mechanism 40, including of slit 48, in a file foruse by a manufacturer, at a design saving step 76.

Using Silicone O-Rings in Dual Action Irrigation Pump

FIG. 7 is a cross-sectional view of the disposable single-pistondual-action pump part 10 of FIG. 1 including silicone O-rings 66, inaccordance with an embodiment of the present invention. The functioningof part 10 is described in FIG. 2 .

Three silicone O-rings 40 (i.e., 66 a, 66 b and 66 c) are fitted in pumppart 10 to seal piston 18 against cylinder so as to establish efficientpumping functionality and to avoid leakages as piston 18 movesbi-directionally to pump the fluid, as described below.

As seen, silicon O-rings 66 a and 66 c are fitted in cylinder 20 in away that O-rings 66 a and 66 c prevent fluid from leaking outside ofpump part 10. O-ring 66 b is fitted over piston 18 perimeter, so as toprevent pumped fluid (i.e., fluid under pressure) from leaking aroundpiston 18 into the volume of cylinder 20 separated by piston 18, whereinthat increased volume serves for fluid intaking. As the piston reversesdirection, O-ring 66 b serves to seal against flow in the oppositedirection.

The example illustration shown in FIG. 7 is chosen purely for the sakeof conceptual clarity. The cross-section, location and number ofsilicone O-rings 66 may vary.

Manufacturing Process of the Pump Part

FIG. 8 is a flow chart describing a manufacturing method of thedisposable single-piston dual-action pump part 11 of FIG. 3 , inaccordance with an embodiment of the present invention.

The process begins with partially assembling disposable dual-actionreciprocating pump part 11, at a pump part assembly step 80. Next,silicone O-rings 66 are fitted into the partially assembled pump part11, at a silicone O-rings fitting step 82. Next, balloon damper 40 isfitted into the partially assembled pump part 11, at a balloon damperfitting step 84. Alternatively or additionally, the pulsation iscontrolled by the disclosed mechanical smoothing mechanism and/or by theprocessor changing the rate of rotation, as described above.

Then, the manufacturing method includes finishing the assembly of pumppart 11 into the disposable dual-action reciprocating pump, at a pumpfull assembly step 86. Finally, the fully assembled pump part 10 ispackaged in a sterile package, at a sterile packaging step 88.

The example flow-chart shown in FIG. 8 is chosen purely for the sake ofconceptual clarity. Only manufacturing steps that are relevant toembodiments of the invention are shown.

Although the embodiments described herein mainly address anon-sterilizable pump part for catheter irrigation, the disclosedsingle-use pump part described herein can also be used in other medicalapplications, such as in injection of contrast agents for medicalimaging and in intravenous infusion.

It will thus be appreciated that the embodiments described above arecited by way of example, and that the present invention is not limitedto what has been particularly shown and described hereinabove. Rather,the scope of the present invention includes both combinations andsub-combinations of the various features described hereinabove, as wellas variations and modifications thereof which would occur to personsskilled in the art upon reading the foregoing description and which arenot disclosed in the prior art. Documents incorporated by reference inthe present patent application are to be considered an integral part ofthe application except that to the extent any terms are defined in theseincorporated documents in a manner that conflicts with the definitionsmade explicitly or implicitly in the present specification, only thedefinitions in the present specification should be considered.

1. A disposable dual-action reciprocating pump part, comprising: aninput port; an output port; a piston and a cylinder, the piston beingconfigured to move bi-directionally inside the cylinder to cause fluidto be pumped from the input port and through the output port, thecylinder and output port being connected by a first channel disposed ona first side of the piston and a second channel disposed on a secondside of the piston; a first non-return valve disposed in the firstchannel such that fluid flows through the first channel and not thesecond channel while the piston moves toward the first channel; a secondnon-return valve disposed in the second channel such that fluid flowsthrough the second channel and not the first channel while the pistonmoves toward the second channel; a rod coupled to the piston, the rodhaving a first portion extending away from the piston in a firstdirection and a second portion extending away from the piston in asecond direction that is opposite to the first direction; a mechanicalsmoothing mechanism, comprising: a guide hub including a guide channelconnected to the rod, the guide channel having a guide profile, acylinder head, a rotary shaft coupled to the cylinder head, a bardisposed though the guide channel and attached to the cylinder head,such that the mechanical smoothing mechanism is configured to induce therod to move back and forth along its axis in the first direction and thesecond direction.
 2. The disposable dual-action reciprocating pump partof claim 1, in which the guide profile is configured to convert arotational movement of the rotary shaft into a variable speed profile ofthe rod.
 3. The disposable dual-action reciprocating pump part of claim2, in which the variable speed profile of the rod comprises a functionof the position of the piston.
 4. The disposable dual-actionreciprocating pump part of claim 1, in which the mechanical smoothingmechanism is configured to induce the rod to move back and forth via arotational movement of the bar in the guide channel.
 5. The disposabledual-action reciprocating pump part of claim 4, in which the rotationalmovement of the bar causes the bar to move in the guide channel.
 6. Thedisposable dual-action reciprocating pump part of claim 5, in which therotational movement of the bar forces the guide hub to translate the rodalong its axis.
 7. The disposable dual-action reciprocating pump part ofclaim 6, in which the attachment of the bar to the cylinder headcomprises the bar being screwed into the cylinder head.
 8. Thedisposable dual-action reciprocating pump part of claim 7, furthercomprising multiple silicone O-rings that are configured to seal thepiston against the cylinder, the multiple silicone O-rings comprising afirst silicone O-ring disposed about the piston, a second siliconeO-ring disposed about the first portion of the rod, and a third siliconeO-ring disposed about the second portion of the rod.